Lubricious coating for medical devices

ABSTRACT

Medical devices having at least a portion thereof coated with a lubricious polymer are disclosed. The lubricious polymer can be, for instance, a hydrogel polymer, such as a quaternary amine acrylate polymer. To bond the lubricious polymer to the surface of the medical device, the medical device is first subjected to a solvent and a multi-functional monomer. The solvent causes the multi-functional monomer to become imbibed into the surface of the medical device. Thereafter, a polymer having lubricious properties is polymerized on the surface of the device. The multi-functional monomer reacts with the polymer coating securely affixing the polymer coating to the device.

RELATED APPLICATIONS

The present application is a continuation in part of U.S. applicationSer. No. 10/325,443, filed on Dec. 19, 2002.

BACKGROUND OF THE INVENTION

Various medical devices are designed to be inserted into a patient toassist in patient care. For example, endotracheal tubes are designed tobe inserted through the mouth and throat of a patient for assisting inrespiration. Further, other devices, such as tracheal suction devicesare used in conjunction with endotracheal tubes to, for instance, removeaccumulated secretions from the lungs of a patient.

In addition to being placed in the throat of a patient, other medicaldevices are designed to be inserted into other areas of the body. Forexample, coronary angioplasty catheters having an inflatable balloon areinserted and guided through blood vessels. Other types of catheters alsoare inserted into other areas of the body such as through the stomachwalls or in the urinary tract.

During insertion of these types of devices, it can sometimes bedifficult to guide the device into a desired location in a patient dueto friction between the device and an adjacent surface. Thus, a needexists for a coating that can be applied to a medical device to reducethe coefficient of friction and make the device much easier to insertinto a patient. Further, a need exists for a biocompatible andlubricious coating that can be applied to medical devices which also hasanti-microbial properties.

SUMMARY OF THE INVENTION

The present invention is generally directed to medical devices having apolymeric portion thereof that has been coated with a lubricioushydrogel polymer. The lubricious coating lowers the coefficient frictionof the polymeric portion of the medical device, which facilitates use ofthe medical device. For example, the lubricious coating makes it easierto insert and guide a medical device into a patient.

In one embodiment, the process of the present invention includes firstproviding a medical device made from a polymer. For example, the medicaldevice can include a portion made from any suitable thermoplastic orthermoset polymer, such as polyvinyl chloride, a urethane, or asilicone.

A surface of the medical device is then contacted with a solvent and amulti-functional monomer. The solvent causes the multi-functionalmonomer to be imbibed into the surface of the medical device. Forexample, in one embodiment, the polymeric surface of the medical devicebecomes solvated and partially dissolves and/or swells in size. Bysolvating the surface of the medical device, the multi-functionalmonomer is capable of either chemically reacting with the surface of thedevice or forming a mechanical interlock with the surface.

After being contacted with the solvent and the multi-functional monomer,the surface of the medical device is dried. The multifunctional monomermay be partially polymerized if desired.

Next, a hydrogel polymer is polymerized on the surface of the medicaldevice. The hydrogel polymer reacts with the multi-functional monomerimbibed into the surface of the device to form a lubricious coating. Forexample, in one embodiment, the multi-functional monomer causes thehydrogel monomer to cross-link. Ultimately, the multi-functional monomerserves to bond the hydrogel polymer to the surface of the device.

The multi-functional monomer can be any suitable monomer capable ofattaching to the surface of the medical device and also reacting withthe hydrogel polymer. The multi-functional monomer can be, for instance,an acrylate (including methacrylates), an acrylamide, a vinylpyrrolidone, a cationic quaternary ammonium monomer, and the like. Whenthe multi-functional monomer is an acrylate, for instance, the monomermay be a triacrylate, a tetraacrylate, a pentaacrylate, a hexaacrylate,or a diacrylate. The acrylate may be alkoxylated. In one embodiment, forinstance, the monomer may be an ethoxylated trimethyolpropanetriacrylate.

Any suitable hydrogel polymer can be used in accordance with the presentinvention. In one embodiment, for instance, the hydrogel polymer is acationic quaternary amine acrylate polymer. In this embodiment, thehydrogel polymer is polymerized on the surface of the medical device byfirst contacting the surface of the medical device with a monomer suchas an acryloyloxyethyl(or propyl)-trialkyl (or aryl)-substitutedammonium salt or an acrylamidoethyl(or propyl)-trialkyl(oraryl)-substituted ammonium salt. In one embodiment, for instance, themedical device can be dipped into a solution containing the abovemonomers. Once the monomers are applied to the surface of the medicaldevice, the monomers can be polymerized by, for instance, exposing themedical device to ultraviolet radiation.

Various medical devices can be treated in accordance with the presentinvention. Such medical devices can include, for instance, trachealsuction devices, endotracheal tubes, catheters, balloons, guidewires,stylets, introducers, and the like.

Of particular advantage, in one embodiment, the lubricious coating canhave inherent anti-microbial properties which can serve to furtherprotect the medical device and the patient during use.

Other features and aspects of the present invention are discussed ingreater detail below.

BRIEF DESCRIPTION OF THE FIGURES

A full and enabling disclosure of the present invention, including thebest mode thereof to one of ordinary skill in the art, is set forth moreparticularly in the remainder of the specification, including referenceto the accompanying figures in which:

FIG. 1 is a perspective view of an endotracheal tube and an aspiratingdevice that may be made in accordance with the present invention;

FIG. 2 is a cross-sectional view of the catheter tube that forms part ofthe aspirating device shown in FIG. 1.

Repeated use of reference characters in the present specification anddrawings is intended to represent the same or analogous features orelements of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Reference now will be made in detail to the embodiments of theinvention, one or more examples of which are set forth below. Eachexample is provided by way of explanation of the invention, notlimitation of the invention. In fact, it will be apparent to thoseskilled in the art that various modifications and variations can be madein the present invention without departing from the scope or the spiritof the invention. For instance, features illustrated or described aspart of one embodiment can be used on another embodiment to yield stilla further embodiment. Thus, it is intended that the present inventioncover such modifications and variations as come within the scope of theappended claims and their equivalents.

In general, the present invention is directed to a lubricious coatingthat can be applied to medical devices. The medical devices that can betreated in accordance with the present invention include, but are notlimited to, devices that are typically inserted into the body of apatient and other devices where low friction surfaces are desired. Byway of example, medical devices that can include a lubricious coatingmade according to the present invention include tracheal devices, suchas endotracheal tubes, aspirating devices and other tracheal suctiondevices, bronchoalveolar lavage catheters, enternal feeding devices,urinary catheters, catheters used in coronary angioplasty, guidewires,stylets, introducers, and the like. The lubricious coating of thepresent invention is particularly designed to be applied to polymericsurfaces that may be contained within the medical device.

Once applied to a medical device, the lubricious coating of the presentinvention lowers the coefficient of friction and facilitates insertionof the device into a patient. Depending upon the medical device treatedin the application, the lubricious coating can also serve to protect themedical device and/or the patient during use of the medical device. Ofparticular advantage, in one embodiment, the lubricious coating of thepresent invention can have anti-microbial properties which further serveto protect patients.

The lubricious coating of the present invention is generally a polymer.For example, the polymer can be a cationic quaternary amine acrylatehydrogel polymer. According to the present invention, the polymer isbonded to a surface of a medical device by first imbibing amulti-functional monomer into the surface of the device. As used herein,the term “imbibing” means that the multi-functional monomer is eitherchemically or mechanically bonded to a polymeric surface. Further, theterm “monomer” means any material capable of polymerizing orcross-linking with a polymer and can include monomers, oligomers,polymers, and the like.

Once the multi-functional monomer is bonded to the surface of themedical device, the surface is contacted with a prepolymer, such as ahydrogel prepolymer. Polymerization is then initiated causing theprepolymer to form into a hydrogel polymer coating. Duringpolymerization, the hydrogel polymer reacts with the multi-functionalmonomer. For instance, in one embodiment, the multi-functional monomercross-links with the hydrogel polymer. In this manner, themulti-functional monomer becomes part of the hydrogel polymer structurewhile simultaneously attaching the hydrogel polymer to the surface ofthe medical device. Ultimately, a lubricious coating is formed on thesurface of the medical device that is securely affixed to the device.

For purposes of illustration, FIG. 1 shows an endotracheal tube 24 inconjunction with an aspirating device 10 that can both be made inaccordance with the present invention. The endotracheal tube 24 is shownplaced in the mouth and throat of a patient 30. In this embodiment, theendotracheal tube 24 includes a fitting 26 which is adapted to engage arespirating device or, alternatively, the aspirating device 10 as shownin FIG. 1.

The aspirating device 10 includes an aspirating catheter tube 12 whichextends along substantially the entire axial length of the device. Thecatheter tube 12 is encased within a tubular sleeve or envelope 14 of aflexible film made from a polymer, such as medical grade polyethylene.

At one end of the aspirating device 10 is a manually operable valve 20.The valve 20 is configured to be connected to a vacuum source duringuse. The valve 20 can be used to control the amount of suction presentin the catheter tube when removing secretions from a patient's lungs.

At the opposite end of the aspirating device 10 is a fitting 16configured to attach to the endotracheal tube 24. In this embodiment,the fitting 16 covers the exposed end of the catheter tube 12 toaccommodate a sterile insertion and retraction of the catheter tube 12into the fitting 26 located at the end of the endotracheal tube 24. Thefitting 16 may be welded or bonded into place at the end of the tubularsleeve 14.

When the aspirating device is being used, the catheter tube 12 ismanually manipulated through the endotracheal tube 24 into the lungs.The envelope 14 surrounding the catheter tube 12 collapses as thecatheter tube is inserted into the patient. Once positioned in thelungs, the catheter tube 12 is used to clear secretions from thepatient's airway.

In accordance with the present invention, the endotracheal tube 24 andthe catheter tube 12 can be treated with the lubricious coating whichfacilitates placement of the medical devices within the patient. Forexample, FIG. 2 shows a cross-section of the catheter tube 12. As shown,the catheter tube 12 includes a coating 40 applied to the exteriorsurface of the catheter tube. In accordance with the present invention,the coating 40 is lubricious and can be made from a hydrogel polymerthat is securely affixed to the surface of the catheter tube. Thecatheter tube can be made from a polymer, such as polyvinyl chloride, aurethane, a silicone, and the like. By applying the coating 40 to thecatheter tube 12, the coefficient of friction of the outside surface ofthe catheter tube is reduced, which in turn lowers the resistance thatis experienced when the catheter tube is being inserted through theendotracheal tube 24.

In addition to coating the outside surface of the catheter tube, theinside of the catheter tube can also be treated in accordance with thepresent invention. Further, the inside and outside surfaces of theendotracheal tube 24 can also be treated as desired.

In addition to the endotracheal tube 24 and the catheter 12 shown inFIG. 1, it should be understood that the lubricious coating of thepresent invention can be applied to various other medical devices aswell. In general, any polymeric part of a medical device where a lowercoefficient of friction is desired can be coated in accordance with thepresent invention.

One embodiment of a process for coating a medical device in accordancewith the present invention will now be described in detail. As discussedabove, the present invention is generally directed to applying a coatingof a quaternary amine acrylate hydrogel polymer to the surface of amedical device. In forming the hydrogel coating, a surface of themedical device is first contacted with a multi-functional monomer. Asused herein, “medical device” means a complete device or any part orcomponent thereof. For example, in many applications, a part for amedical device will be treated in accordance with the present inventionand then later assembled into the device.

The medical device can be made from any suitable thermoplastic orthermoset polymer capable of forming a mechanical or chemical attachmentto the multi-functional monomer. Suitable polymers include, forinstance, silicones and urethanes. In one particular embodiment, forinstance, the medical device can be made from polyvinyl chloride.

In order to attach the multi-functional monomer to the surface of thepolymeric medical device, the medical device is also contacted with asolvent that is capable of solvating or swelling the polymer. Thesolvent and the multi-functional monomer can be first combined togetherand then contacted with the medical device or can contact the medicaldevice sequentially. In one embodiment, the solvent partially dissolvesthe surface of the medical device or otherwise causes the polymericsurface to swell. During swelling and partially dissolving, themulti-functional monomer can form a mechanical interlock with thesurface. In other embodiments, the multi-functional monomer can alsoundergo a chemical reaction with the surface of the polymer.

Various solvents can be used in accordance with the present invention.Such solvents include, for instance, dimethylsulfoxide (DMSO), acetone,alcohols, methylethyl ketone, toluene, xylene, N,N-dimethyl formamide(DMF), tetrahydrofuran and the like. The particular solvent chosen foran application will depend upon the type of polymer being coated and thetype multi-functional monomer used.

For example, when the medical device contains polyvinyl chloride, thesolvent may be DMSO and ketones. If the medical device contains aurethane, however, the solvent may be DMF or tetrahydrofuran. If themedical device contains silicone, the solvent chosen may be toluene orxylene.

The multi-functional monomer used in the present invention should becapable of mechanically or chemically bonding to the surface of themedical device and later reacting with the hydrogel polymer that isformed on the surface of the medical device. For example, amulti-functional monomer can be used that will cause cross-linking in aquaternary amine acrylate hydrogel polymer.

The multi-functional monomer can be, for instance, an acrylate such as acationic quaternary ammonium monomer, other ammonium compounds, anacrylamide, or a vinyl pyrrolidone. The multi-functional monomer may bebifunctional, trifunctional, tetrafunctional, pentafunctional, orhexafunctional.

Difunctional monomers which may be used in the present invention includebutylene glycol diacrylate, butylene glycol dimethacrylate, butanedioldiacrylate, butanediol dimethacrylate, hexanediol diacrylate, hexanedioldimethacrylate, aliphatic dimethacrylate monomer, alkoxylated aliphaticdiacrylate, alkoxylated cyclohexane dimethanol diacrylate, alkoxylatedhexanediol diacrylate, alkoxylated neopentyl glycol diacrylate, aromaticdimethacrylate monomer, caprolactione modified neopentylglycolhydroxypivalate diacrylate, cyclohexane dimethanol diacrylate,cyclohexane dimethanol dimethacrylate, diethylene glycol diacrylate,diethylene glycol dimethacrylate, dipropylene glycol diacrylate,ethoxylated (10) bisphenol a diacrylate, ethoxylated (2) bisphenol adimethacrylate, ethoxylated (3) bisphenol a diacrylate, ethoxylated (30)bisphenol a diacrylate, ethoxylated (30) bisphenol a dimethacrylate,ethoxylated (4) bisphenol a diacrylate, ethoxylated (4) bisphenol adimethacrylate, ethoxylated (8) bisphenol a dimethacrylate, ethoxylatedbisphenol a dimethacrylate, ethoxylated bisphenol a dimethacrylate,ethoxylated (10) bisphenol dimethacrylate, ethoxylated (6) bisphenol adimethacrylate, ethylene glycol dimethacrylate, hydroxypivalaldehydemodified trimethylolpropane diacrylate, neopentyl glycol diacrylate,neopentyl glycol dimethacrylate, polyethylene glycol (200) diacrylate,polyethylene glycol (400) diacrylate, polyethylene glycol (400)dimethacrylate, polyethylene glycol (600) diacrylate, polyethyleneglycol (600) dimethacrylate, polyethylene glycol dimethacrylate,polypropylene glycol dimethacrylate, propoxylated (2) neopentyl glycoldiacrylate, tetraethylene glycol diacrylate, tetraethylene glycoldimethacrylate, triethylene glycol diacrylate, triethylene glycoldimethacrylate, tripropylene glycol diacrylate, and the like. The abovedifunctional monomers are all available from the Sartomer Company, Inc.of Exton, Pa.

Trifunctional monomers that may be used in the present invention includeethoxylated (15) trimethylolpropane triacrylate, ethoxylated (3)trimethylolpropane triacrylate, ethoxylated (6) trimethylolpropanetriacrylate, ethoxylated (9) trimethylolpropane triacrylate, ethoxylated(20) trimethylolpropane triacrylate, highly propoxylated (5.5) glyceryltriacrylate, low viscosity trimethylolpropane triacrylate,pentaerythritol triacrylate, propoxylated (3) glyceryl triacrylate,propoxylated (3) trimethylolpropane triacrylate, propoxylated (6)trimethylolpropane triacrylate, trimethylolpropane triacrylate,trimethylolpropane trimethacrylate, tris (2-hydroxy ethyl)isocyanuratetriacrylate, and the like. The above trifunctional monomers are allavailable from the Sartomer Company, Inc. of Exton, Pa.

Tetrafunctional, pentafunctional and hexafunctional monomers that may beused in the present invention include di-trimethylolpropanetetraacrylate, dipentaerythritol pentaacrylate, ethoxylated (4)pentaerythritol tetraacrylate, low viscosity dipentaerythritolpentaacrylate, pentaacrylate ester, pentaerythritol tetraacrylate,caprolactone modified dipentaerythritol hexaacrylate, and the like. Theabove monomers are all available from the Sartomer Company, Inc. ofExton, Pa.

All of the above listed monomers are acrylates. As shown above, theacrylates may be alkoxylated using, for instance, ethoxylate groups orpropoxylate groups. Other acrylates include cationic quaternary ammoniummonomers. Examples of cationic quaternary ammonium monomers includeN,N-Dimethylaminoethyl acrylate DMS (dimethyl sulfate),N,N-Dimethylaminoethyl acrylate MC (methyl chloride),N,N-Dimethylaminoethyl methacrylate DMS, N,N-Dimethylaminoethylmethacrylate MC, or Diallyldimethylammonium chloride, which are allcommercially available from Ciba Specialty Chemicals. Other quaternaryammonium monomers that may be used include acryloxethyldimethyl benzylammonium chloride, acryloxyethyltrimethyl ammonium chloride,methacryloxyethyldimethyl benzyl ammonium chloride, ormethacryloxyethyltrimethyl ammonium chloride, which may be obtainedcommercially from Atofina.

Other examples of multi-functional monomers that can be used in thepresent invention include methylene-bis-acrylamide (MBA) and diethyleneglycol diacrylate, which are both commercially available fromPolysciences, Inc., Warrington, Pa. Additional examples ofmulti-functional monomers which may be acceptable for use in the presentinvention include ethylene glycol diacrylate, triethyleneglycol-bis-methacrylate, ethylene glycol-bis-methacrylate, ethyleneglycol-dimethacrylate, bisacrylamide, triethyleneglycol-bis-acrylate,3,3′-ethylidene-bis (N-vinyl-2-pyrrolidone), trimethylolpropanetrimethacrylate, glycerol trimethacrylate, polyethylene glycoldimethacrylate, and other polyacrylate and polymethacrylate esters.

In addition to the solvent and the multi-functional monomer, the surfaceof the medical device can also be contacted with an initiator. Ifneeded, the initiator can be used to initiate polymerization of thehydrogel polymer that is to be formed on the surface.

Examples of initiators which may be used include, for example, IRGACURE®184 (1-hydroxycyclohexyl phenyl ketone), and DAROCURE® 1173(α-hydroxy-1, αdimethylacetophenone) which are both commerciallyavailable from Ciba-Geigy Corp. These UV catalysts are desired in someapplications because they are non-yellowing. Additional examples ofinitiators (which may be photo initiators or thermal initiators) mayinclude benzoyl peroxide, azo-bis-isobutyro-nitrile, di-t-butylperoxide, bromyl peroxide, cumyl peroxide, lauroyl peroxide, isopropylpercarbonate, methylethyl ketone peroxide, cyclohexane peroxide,t-butylhydroperoxide, di-t-amyl peroxide, dicymyl peroxide, t-butylperbenzoate, Benzoin alkyl ethers (such as benzoin, benzoin isopropylether, and benzoin isobutyl ether), benzophenones (such as benzophenoneand methyl-o-benzoyl benzoate), acetophenones (such as acetophenone,trichloroacetophenone, 2,2-diethoxyacetophenone,p-t-butyltrichloro-acetophenone, 2,2-dimethoxy-2-phenylacetophenone, andp-dimethylaminoacetophenone), thioxanthones (such as xanthone,thioxanthone, 2-chlorothioxanthone, and 2-isopropyl thioxanthone),benzyl 2-ethyl anthraquinone, methylbenzoyl formate,2-hydroxy-2-methyl-1-phenyl propane-1-one,2-hydroxy-4′-isopropyl-2-methyl propiophenone, e-hydroxy ketone,tet-remethyl thiuram monosulfide, allyl diazonium salt, and acombination of camphorquinone or 4-(N,N-dimethylamino)benzoate.

The medical device may be contacted with a solution comprised of one ormore of the following components: a solvent, a multi-functional monomer,and an initiator, or the medical device may be contacted with theseparate components in sequential steps. In one particular embodiment, asolution can be formed containing the solvent, the multi-functionalmonomer, and the initiator. The multi-functional monomer can be presentin the solution in an amount from about 5% to about 50% by weight. Theinitiator can be present in the solution in an amount from about 0.05%to about 5.0% by weight. The medical device can be contacted with thesolution, such as being dipped in the solution. In particular, thesurface of the medical device can be contacted with the solution in anamount of time sufficient for the polymeric surface to either swelland/or partially dissolve. For example, the surface of the medicaldevice optionally may be contacted with solution at room temperature forabout 30 seconds to about 3 minutes.

If contacted with the solution, the medical device may be dried ifdesired although this step is not necessary. For instance, the medicaldevice can be heated or can simply be air dried. In this manner, themulti-functional monomer becomes imbibed into the surface of thepolymer.

Also optional, polymerization may be initiated in a portion of themulti-function monomer. Partially polymerizing the multi-functionalmonomer may serve to create a better interlock with the surface of themedical device. Further, only a portion of the multi-functional monomermay be polymerized in order to leave active functional sites remaining.In some embodiments, it should be understood that partial polymerizationof the multi-functional monomer may not be necessary.

Once the multi-functional monomer is imbibed into the surface of themedical device and mechanically or chemically attached to the medicaldevice, the surface of the medical device is then contacted with amonomer or pre-polymer capable of forming the hydrogel polymer. In oneembodiment, the hydrogel polymer that is formed on the surface of themedical device is a cationic quaternary amine acrylate polymer. Forexample, the hydrogel polymer can comprise the following:

wherein n is an integer of 2 to 3; R′, R″ and R′″ are independentlyselected from the group consisting of H,C₁ to C₁₆ alkyl, aryl,arylamine, alkylamine, alkaryl and aralkyl; X is selected from the groupconsisting of O and NH; and Y⁻ is an acceptable anionic counterion tothe N⁺ of the quaternary amine.

Alkyl groups may be lower alkyl, of C1, to C8 with methyl or ethylgroups being particularly desired. Aryl is desireably phenyl but can beany suitable aromatic moiety such as those selected from the groupconsisting of phenyl, thiophenyl, naphthyl, biphenyl, pyridyl,pyrimidinyl, pyrazyl, pyridazinyl, furyl, thienyl, pyrryl, quinolinyland bipyridyl and the like. Representative of an aralkyl grouping isbenzyl and representative of an alkaryl grouping is tolyl. X isdesireably O or NH. Representative of counterions represented by Y⁻ aremembers selected from the group consisting of Cl⁻, Br⁻, HSO₄ ⁻, andCH₃SO₄ ⁻ with Cl⁻ being particularly desired. Alkyl groups can bestraight or branched chained and alkyl and aryl groups can besubstituted by non-interfering substituents that do not obstruct withthe functionality of the polymers.

Monomers or pre-polymers that can be used to form the above hydrogelsinclude the following:

where R′, R″ and R′″, X, Y— have the meanings given above in Formula Iand m is an integer greater than 50,000. Polymerization is brought aboutby methods known in the art such as free radical curing with aninitiator induced polymerization in the presence of water byultra-violet curing and a multi-functional cross-linking agent or byanionic 1,2 alkoxy anion induced polymerization.

Examples of specific quaternary amine cationic acrylate ester or amidemonomers that may be polymerized are shown in following Formulas II, IV,V and IV.

Formula III shows acryloyloxyethyltrimethyl ammonium chloride which isavailable from CPS Chemical Co.

Formula IV shows acryloyloxyethyltrimethyl ammonium methyl sulfate whichis available from Allied Colloid Co.

Formula V shows acrylamidopropyltrimethyl ammonium chloride which isavailable from Stockhausen (Germany).

Formula VI shows acryloxyethyldimethylbenzyl ammonium chloride which isavailable from Elf Atochem. As shown in the above formula, Y⁻ may berepresented by the counterion chloride.

Various methods can be used to apply the monomer to the surface of themedical device. For instance, in one embodiment, the monomer can becombined with water and sprayed onto the medical device. In anotherembodiment, the medical device can be dipped into a solution containingthe monomer. For example, in one embodiment, the monomer can be presentin the solution in an amount from about 50% to about 98% by weight,particularly from about 70% to about 90% by weight, and applied to thesurface of the medical device.

The viscosity of the monomer solution can be adjusted depending upon theparticular application and circumstances. In general, when dipping themedical device into the solution, higher viscosities will cause more ofthe monomer to remain on the surface of the device. Thus, if thickercoatings are desired, the viscosity can be increased. The viscosity ofthe solution can be increased by minimizing the amount of water in thesolution. Additionally, thickeners, such as a polyacrylamide, can beadded to the solution. The viscosity of the solution can also beincreased by partially polymerizing the monomer.

In addition to the monomer and a thickener, the solution can containother various ingredients. For instance, if desired, an initiator asdescribed above can also be contained within the monomer solution.Further, if desired more of the multi-functional monomer can also becombined with the monomer and applied to the surface of the medicaldevice.

Once the monomer has been applied to the medical device, the monomer ispolymerized to form the hydrogel polymer. During polymerization, themonomer also reacts with the multi-functional monomer previously appliedto the medical device. For example, in one embodiment, themulti-functional monomer causes the hydrogel to cross-link.

Polymerization of the polymer can be initiated in various ways. Ingeneral, the manner in which the hydrogel polymer is polymerized dependsupon the particular initiator chosen. For example, polymerization of thepolymer can occur when the monomer is exposed to light energy, heat orto a particular chemical agent.

In one embodiment, polymerization of the monomer to form the hydrogelpolymer is caused by exposing the medical device to ultraviolet light.The ultraviolet light may be, for instance, non-ionizing and can have awavelength of at least about 200 nanometers. For example, in oneembodiment, after the monomer is applied to the medical device, themedical device can be exposed to one or more 600-watt ultraviolet lamps.For example, in one embodiment, circular xenon lamps can be used. Themedical device may be exposed to the ultraviolet rays until the hydrogelpolymer is cured.

Upon curing, the hydrogel polymer becomes bonded to the medical devicethrough reaction with the multi-functional monomer. The hydrogel polymerlowers the coefficient of friction on the surface of the medical deviceand provides a lubricious coating. Further, in some embodiments, thehydrogel polymer can also possess anti-microbial properties which can beparticularly advantageous in medical applications.

The thickness of the hydrogel polymer on the medical device can dependon the particular application. For most embodiments, however, thethickness of the coating will be from about 0.1 to about 10 milshydrated. In order to produce thicker coatings, in some embodiments, themedical device can be dipped into the monomer multiple times. Themonomer can be polymerized and cured in between each dipping step or canbe polymerized and cured all in a single step.

If desired, in some embodiments, after the hydrogel polymer ispolymerized the medical device can also be soaked in an aqueoussolution, such as a saline solution, to remove any residual monomer.

These and other modifications and variations to the present inventionmay be practiced by those of ordinary skill in the art, withoutdeparting from the spirit and scope of the present invention, which ismore particularly set forth in the appended claims. In addition, itshould be understood that aspects of the various embodiments may beinterchanged both in whole or in part. Furthermore, those of ordinaryskill in the art will appreciate that the foregoing description is byway of example only, and is not intended to limit the invention sofurther described in such appended claims.

1. A medical device comprising: a surface configured to move in relationto an adjacent surface; and a lubricious coating applied to the surface,the lubricious coating comprising a quaternary amine acrylate hydrogelpolymer that has been cross-linked to a multi-functional monomer, themulti-functional monomer having been imbibed into the surface of themedical device, the multi-functional monomer comprising an acrylate oran ammonium compound.
 2. A medical device as defined in claim 1, whereinthe surface of the device is made from a thermoplastic or a thermoset.3. A medical device as defined in claim 1, wherein the surface of thedevice is made from polyvinyl chloride.
 4. A medical device as definedin claim 1, wherein the quaternary amine acrylate hydrogel polymer isformed from a monomer having the structure:

wherein n is an integer of 2 to 3; R′, R″ and R′″ are independentlyselected from the group consisting of H,C₁ to C₁₆ alkyl, aryl,arylamine, alkylamine, alkaryl and aralkyl; X is selected from the groupconsisting of O and NH; and Y⁻ is an acceptable anionic counterion tothe N⁺ of the quaternary amine.
 5. A medical device as defined in claim1, wherein the medical device comprises tracheal suction device, acatheter, a guidewire, a stylet, an enteral feeding device, anintroducer, or an endotracheal tube.
 6. A medical device as defined inclaim 1, wherein the surface of the device is made from a silicone or aurethane.
 7. A medical device as defined in claim 1, wherein thequaternary amine acrylate hydrogel polymer comprisesacryloyloxyalkyl-trialkyl-substituted ammonium salt, anacryloyloxyalkyl-aryl-substituted ammonium salt, anacrylamidoalkyl-trialkyl-substituted ammonium salt, or anacrylamidoalkyl-aryl-substituted ammonium salt.
 8. A medical device asdefined in claim 1, wherein the quaternary amine acrylate hydrogelpolymer comprises acryloyloxyethyltrimethyl ammonium chloride, oracryloyloxyethyltrimethyl ammonium methyl sulfate.
 9. A medical deviceas defined in claim 1 wherein the multi-functional monomer comprises analkoxylated acrylate.
 10. A medical device as defined in claim 1 whereinthe multi-functional monomer comprises a triacrylate.
 11. A medicaldevice as defined in claim 1, wherein the multi-functional monomercomprises a tetraacrylate, a pentaacrylate, a hexaacrylate, or adiacrylate.
 12. A medical device as defined in claim 1, wherein themulti-functional monomer comprises an ethoxylated trimethylolpropanetriacrylate, a propoxylated glyceryl triacrylate, trimethylolpropanetriacrylate, pentaerythritol triacrylate, a propoxylated glyceryltriacrylate, a propoxylated trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, tris (2-hydroxy ethyl) isocyanuratetriacrylate, di-trimethylolpropane tetraacrylate, dipentaerythritolpentaacrylate, an ethoxylated pentaerythritol tetraacrylate, adipentaerythritol pentaacrylate, a pentaacrylate ester, pentaerythritoltetraacrylate, or a caprolactone modified dipentaerythritolhexaacrylate.
 13. A medical device as defined in claim 1, wherein themulti-functional monomer comprises N,N-Dimethylaminoethyl acrylatedimethylsulfate, N,N-Dimethylaminoethyl acrylate methylchloride,N,N-Dimethylaminoethyl methacrylate dimethylsulfate,N,N-Dimethylaminoethyl methacrylate methylchloride,Diallyldimethylammonium chloride, acryloxyethyldimethyl benzyl ammoniumchloride, acryloxyethyltrimethyl ammonium chloride,methacryloxyethyldimethyl benzyl ammonium chloride, ormethacryloxyethyltrimethyl ammonium chloride.
 14. A medical device asdefined in claim 1, wherein the multi-functional monomer comprises anethoxylated trimethylolpropane triacrylate.